1. Field of the Invention
The invention relates to the field of bicycles driven by shafts and, more particularly, to the field of one and two-wheel drive bicycles having one or both of the front wheel and the rear wheel driven by a series of shafts that are themselves coupled to a transmission having a plurality of ring gears.
2. Description of the Prior Art
Two-wheel drive bicycles are known in the art and generally comprise either a shaft drive, a chain or belt drive, a cable drive or some combination thereof. For example, U.S. Pat. No. 4,479,660 (Pattison) describes an endless belt drive system for the front wheel that is driven by the bicycle pedals. In a somewhat similar vein, U.S. Pat. No. 4,773,662 (Phillips) describes a second chain drive system for the front wheel that is driven by an auxiliary hand crank. A cable drive system, on the other hand, is described in U.S. Pat. No. 5,052,705 (Ringle). Instead of being driven by the bicycle pedals or an auxiliary hand crank, the Ringle cable drive is driven by the rotation of the rear wheel, which is itself driven in standard fashion by the bicycle pedals. A similar cable drive is described in U.S. Pat. No. 5,184,838 (Becoat). A combination of chain drives and shafts is described in U.S. Pat. No. 5,158,314 (Farras Pinos). In a manner similar to the Ringle cable drive, the Farras Pinos combination drive is driven by the rotation of the rear wheel. A similar combination of chain drives, cable drives and/or flexible shafts is described in U.S. Pat. No. 5,224,725 (Erlston) and in U.S. Pat. No. 5,332,244 (Turner et al.). Other combinations of drive mechanisms are described in, for example, U.S. Pat. No. 6,095,540 (Kim), U.S. Pat. No. 6,161,854 (Christini et al.), U.S. Pat. No. 6,406,047 (Sawyer, Jr.) and U.S. Pat. No. 6,419,255 (Chang et al.).